1. Field of the Invention
This invention is particularly concerned with the spherical shaping of a reflective film that is initially a frustum of a cone in flat pattern.
2. Description of the Prior Art
The art of shaping films of reflective character seems fairly well developed in relation to solar collectors. Examples of such film forming are found in U.S. Pat. Nos. Nelson 4,115,177 of Sept. 19, 1978; Simpson 4,173,397 of Nov. 6, 1979; Bronstein 4,293,192 of Oct. 6, 1981; Winders 4,268,332 of May 19, 1981; and Hutchison 4,372,027 of Feb. 8, 1983.
In the field of forming parts for automotive and aircraft usage, using films of appropriate composition, examples presently known include U.S. Pat. Nos. Clapp et al 3,020,596 of Feb. 13, 1962; Bonza et al 3,041,668 of July 3, 1962; DeMuth 3,118,182 of Jan. 21, 1964; Helwig 2,142,445 of Jan. 3, 1939; Mattimoe et al 3,293,343 of Dec. 20, 1966; and Shields et al 2,817,117 of Dec. 24, 1957.
The prior art examples are not particularly concerned with the forming of a thin film into a two-dimensional configuration for use as a mirror in pilot training simulators where the film is treated with a uniform coating of highly reflective material and then held in a spherical shape with its center at a known location for pilot viewing of that surface. The problem encountered in achieving the desired spherical shaping is associated with shaping the ends of the film so as to minimize distortion as much as possible.